In the packaging industry, particularly the food packaging industry for liquids, containers are typically fabricated out of glass, plastic or coated cardboard (i.e. milk containers). In filling such containers, the shape of the container is important to the filling process. For example, there presently exists a large number of filling facilities using round fill line equipment for round containers i.e. round in the sense of having a circular cross section along its longitudinal axis at the top and bottom of the container. Such equipment also provides for the filling of hot liquid into the container.
Such hot filling of round containers is very popular but is predominated by the use of glass containers. One of the reasons glass is typically used in a hot fill situation is that the container must be fairly rigid so that the vacuum collapse after the filling of the hot liquid does not cause the container to distort. While it is desireable to use containers made of different material such as plastic which is relatively inexpensive, because of the flexible nature of such material, especially with thin gauges, distortion of the product does occur due to the vacuum collapse. This obviously renders the resulting product unappealing from a marketing stand point.
Thus there exists a need for a plastic container which can be used in containing hot filled product without the distorting effect heretofore realized.